Mandibular reconstruction using nonvascularized autogenous bone grafting

The Strategy of Delayed Reconstruction of the Mandible in War Injuries

The most common causes of mandibular defects are ablative surgery of benign or malignant tumors, severe trauma, inflammatory diseases, and osteoradionecrosis. War injuries are another cause for mandibular defect. Reconstruction of the mandible is considered a challenge to the maxillofacial surgeon due to the accompanying functional and cosmetic importance. The object of this article was to show the role of nonvascularized bone graft in the reconstruction of segmental defect of the mandible resulted from projectiles and its snags. Seventeen patients underwent reconstruction of defect in the body of the mandible using non-vascularized iliac bone graft,in sixteen patients the grafts were fixed by reconstruction plate and in one by stainless-steel wire. In the emergency phase in which life-saving measures were done, in the immediate phase, treatments of associated facial and systemic injuries were carried out. The delayed phase includes the reconstruction of the residual defects and rehabilitation. A total of 17 male patients with a mean age of 34.5 years underwent reconstructive surgery, the time lapse between the injury and the delayed phase of treatment ranged from 20 days to 3 months. The size of the defects ranged from 4 to 7 cm. Treatment was considered successful in 15 patients (88.2%) in whom the grafts were incorporated to mandible with improvement of facial contour and symmetry and satisfactory occlusion of the remaining teeth. Nonvascularized bone graft is considered a feasible option for the reconstruction of a relatively small mandibular defect, especially in ascetic conditions for its role in improving facial appearance and to less extent functional benefit and more advanced method for the reconstruction needed to be introduced especially in war injuries.

Acceleration of bone-defect repair by using A-W MGC loaded with BMP2 and triple point-mutant HIF1α-expressing BMSCs

Background

The goal of this study is to explore the effects of A-W MGC (apatite-wollastonite magnetic bioactive glass-ceramic) loaded with BMP2 (bone morphogenetic protein 2)- and HIF1α^mu (hypoxia-inducible factor 1 mutation)-expressing BMSCs (bone marrow mesenchymal stem cells) on the bone defect repair.

Methods

(1) BMSCs were infected with viral solution containing BMP2 and HIF1α^mu with the best MOI (multiplicity of infection). The efficiency was observed via hrGFP (human renilla reniformis green fluorescent protein). (2) The cells were divided into five groups (A–E), and ALP (alkaline phosphatase) activity was measured. (3) BMP2 and HIF1α (hypoxia-inducible factor 1α) protein were measured. (4) A-W MGC was loaded with BMSCs that contain the genes and implanted into the bone defect model. The animals were sacrificed 8 and 12 weeks later. (5) The healing was measured with X-ray, histology, and biomechanics.

Results

(1) BMSCs in A–D showed high transfection efficiency. (2) ALP in A and B was higher than the others (p = 0.041 or 0.038); A was higher than B (p = 0.038); (3) BMP2 in A and B was higher than the others (p = 0.014). HIF1α in A and C was higher than the others (p = 0.020). (4) 8 and 12 weeks after, an X-ray indicated that bone defect was nearly fully repaired in A and C. (5) 12 weeks after, the bone remodeling was complete in A and C. (6) The flexural strength in A and C was stronger than the others (p = 0.043).

Conclusion

Engineered A-W MGC with BMP2 and HIF1α^mu-expressing BMSCs exhibits comparable therapeutic effects of bone-defect repair as an autologous bone graft.

Graft necrosis occurred after iliac crest reconstruction after mandibular segmental resection of ameloblastoma

Ameloblastoma is an uncommon benign odontogenic neoplasm of the maxillofacial region constituting less than 1% of tumors of the oral cavity. Ameloblastomas have been categorized broadly into 3 biologic variants: cystic (unicystic), solid, and peripheral. Unicystic ameloblastoma is a rare and less aggressive variant of ameloblastoma. The aim of this report is to describe a case of cystic ameloblastoma treated with segmental resection and iliac graft reconstruction. The possible reasons of graft failure seen in our patient at the early stage of the healing were also discussed.

Huge desmoplastic fibroma of the paediatric mandible: surgical considerations and follow-up in three cases

The desmoplastic fibroma is a rare locally aggressive spindle-cell proliferation made up of fibroblasts/myofibroblasts immersed in a dense collagenic stroma. Head and neck localisation of desmoplastic fibromas is even more rare and the literature is limited to small case series and reviews. A comprehensive review of the English literature from 1968 to 2011 revealed only 79 cases of mandibular desmoplastic fibromas and only 18 (22%) in patients under 4 years of age. Complete resection with clear margins is the surgical first option, but it can be difficult to achieve in the paediatric mandible, especially for giant tumours as the three reported here. Mandibular reconstruction in these cases is mandatory to ensure correct craniofacial development. The authors present three cases of huge mandibular desmoplastic fibromas in paediatric patients treated with mandibulectomy and immediate reconstruction using rib grafts. Indications, reconstructive options and results are discussed.

Osteosarcomas of the mandible: are they different from other tumor sites?

BACKGROUND

Osteosarcomas of the mandible (MOS) affect 1/10 million persons/year, mostly the young adult. Due to lack of specific data, the treatment of MOS is extrapolated from that of extragnathic OS but varies widely between institutions.

MATERIALS AND METHODS

We aimed at providing a focused description of MOS histologies and grades through the English literature, at determining the evidence-based role of chemotherapy, of adjuvant radiation therapy and the potential of reconstructive surgery tailored through modern pre-operative multi-modal imaging.

RESULTS

The estimated proportion of high grade MOS was 58%. However, low-grade MOS may be underestimated as they are mostly reported as case reports. The intermediate grade was hardly found in the literature. Estimated weighted-mean proportions of chondroblastic and osteoblastic MOS were 37% and 46%, respectively. Multimodal imaging modalities including MRI has a great potential for accurate pre-operative assessment of tumor extensions into bone and soft tissues. Surgery is the mainstay of treatment and margins the most important factor. The role of neoadjuvant chemotherapy in treating occult systemic metastases and in increasing the probability of clear margins is controversial, as well as the histology-dependent response to chemotherapy. The role of adjuvant radiotherapy (mostly proposed for positive margins) and/or adjuvant chemotherapy is still controversial. Crude survival is around 77% and local control around 67%. Local failure is the main cause of death in MOS compared to extragnathic sites.